{"id":5647,"date":"2026-01-06T22:46:19","date_gmt":"2026-01-06T17:16:19","guid":{"rendered":"https:\/\/vajiramandravi.com\/upsc-exam\/?p=5647"},"modified":"2026-01-13T17:18:19","modified_gmt":"2026-01-13T11:48:19","slug":"pslv-polar-satellite-launch-vehicle","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/upsc-exam\/pslv-polar-satellite-launch-vehicle\/","title":{"rendered":"Polar Satellite Launch Vehicle, Working, Types, PSLV Stages"},"content":{"rendered":"<p><strong>The Polar Satellite Launch Vehicle <\/strong>(PSLV) is <strong>India's third-generation launch vehicle<\/strong>. It is the first Indian launch vehicle to be fitted with <strong>liquid stages<\/strong>. The PSLV is an indigenously built expendable launch system of the <strong>Indian Space Research Organisation<\/strong><strong> (ISRO).<\/strong> After its initial successful launch in October 1994, PSLV established itself as a dependable and adaptable workhorse launch vehicle in India. The vehicle has launched several Indian and foreign customer satellites. Furthermore, the vehicle successfully launched two spacecraft, \"<strong>Chandrayaan-1\u201d<\/strong> in 2008 and \u201c<strong>Mars Orbiter Spacecraft<\/strong>\u201d in 2013, which later flew to the Moon and Mars, respectively.<\/p>\r\n<p>In addition to LEO satellite launches, PSLV has launched <strong>satellites<\/strong> for <strong>communication<\/strong>, meteorology, navigation, scientific studies, and space exploration.<\/p>\r\n<h2>Characteristic Features of PSLV<\/h2>\r\n<p>The PSLV is an expendable launch vehicle that can place remote sensing satellites into <strong>sun-synchronous orbit <\/strong>(SSO) and small-sized spacecraft into <strong>geostationary transfer orbit <\/strong>(GTO).<\/p>\r\n<ul>\r\n\t<li>PSLV's long series of consecutive successes, as well as its multi-satellite launch capability, have cemented its credibility as a dependable, adaptable, and cost-effective launcher in the worldwide market. It also launched India\u2019s first space observatory, <strong>Astrosat<\/strong>.<\/li>\r\n\t<li><strong>Workhorse of India: <\/strong>PSLV earned its title 'the Workhorse of ISRO by successfully delivering several satellites to <strong>Low Earth Orbit. <\/strong>Due to its unmatched reliability, PSLV has been used to launch various satellites.<\/li>\r\n\t<li><strong>Launches in various orbits: <\/strong>PSLV is a versatile vehicle capable of launching satellites into <strong>LEO <\/strong>(Low inclination, SSO), <strong>Sub-GTO<\/strong>, and <strong>GTO.<\/strong><\/li>\r\n\t<li><strong>Payload: <\/strong>The PSLV is capable of placing multiple payloads into orbit, thus multi-payload adaptors are used in the payload fairing.\r\n\r\n<ul>\r\n\t<li><strong>Payload Capacity to SSPO <\/strong>(Sun-Synchronous Polar Orbits)<strong>: <\/strong>It is capable of carrying up to 1,750 kg of payload to SSPO at 600 km altitude.<\/li>\r\n\t<li><strong>Payload to Sub GTO: <\/strong>1,425 kg.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Configurations of PSLV:<\/strong> The launch vehicle can be customised to fly in three different configurations according to the mission requirements and weighs 229,000, 296,000 or 320,000 kg.<\/li>\r\n<\/ul>\r\n<p><strong>Also Read: <a href=\"https:\/\/vajiramandravi.com\/current-affairs\/pslv-c62-mission\/\" target=\"_blank\">PSLV C62 Mission<\/a><\/strong><\/p>\r\n<h2>Four Stages of PSLV<\/h2>\r\n<p>The PSLV is a four-stage rocket in which the first three spent stages of the rocket fall into the ocean while the last stage (PS4), which launches the satellite into orbit, ends up as <strong>space trash.<\/strong><\/p>\r\n<figure class=\"table\">\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td class=\"tb-color\" colspan=\"2\"><strong>Four PSLV Stages with Functions<\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>First Stage: PS1<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- PSLV employs an S139 <strong>solid rocket<\/strong> motor supplemented by six solid strap-on boosters.<\/p>\r\n<p>- It generates the tremendous amount of <strong>thrust <\/strong>required to lift all 1,750 kilograms of the PSLV off the launchpad.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>Second Stage: PS2<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- PSLV uses an <strong>Earth-storable liquid rocket engine<\/strong> for its second stage, known as the <strong>Vikas engine<\/strong>.<\/p>\r\n<p>- Liquid engines in the PSLV give the rocket better bang for the buck for <strong>rocket fuel.\u00a0<\/strong><\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>Third Stage: PS3<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>- The third stage of PSLV is a <strong>solid rocket motor<\/strong> that provides the upper stages with high thrust after the <strong>atmospheric phase <\/strong>of the launch.<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>Fourth Stage: PS4<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- The fourth stage is a <strong>liquid <\/strong>stage with <strong>twin engines.<\/strong> - This stage is responsible for injecting the PSLV payloads into their desired <strong>orbits<\/strong>.<\/p>\r\n<p>- It uses two <strong>(earth-storable) liquid engines<\/strong> to provide <strong>rocket thrust <\/strong>and may be turned on several times to discharge its payload in batches.<\/p>\r\n<ul>\r\n\t<li><strong>Example:<\/strong> In the <strong>PSLV-C43 mission<\/strong>, where Stage 4 engineers were cut off and switched on three times for 31 satellites.<\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n<h3>PSLV Orbital Experimental Module (POEM)<\/h3>\r\n<p>The POEM is a platform for <strong>conducting in-orbit experiments<\/strong> using the final, and otherwise discarded, stage of ISRO's workhorse rocket, the <strong>Polar <\/strong><strong>Satellite Launch Vehicle.<\/strong><\/p>\r\n<ul>\r\n\t<li>PS4 stage will orbit the Earth as a stabilised platform.\r\n\r\n<ul>\r\n\t<li>Dedicated <strong>Navigation Guidance and Control systems <\/strong>are used to achieve attitude stabilisation.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li>POEM gets its <strong>electricity from solar panels <\/strong>installed around the PS4 tank and a lithium-ion battery.\r\n\r\n<ul>\r\n\t<li><strong>For example,<\/strong> recently, POEM-3, India's unique low-cost space platform, was launched utilising the spent PS4 stage of the <strong>PSLV-C58 vehicle<\/strong>, which launched <strong>XPoSat<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h2>Variants of PSLV<\/h2>\r\n<p>The PSLV is classified into several variations, including the core-alone version<strong> (PSLV-CA), PSLV-G, and PSLV-XL variants.<\/strong><\/p>\r\n<ul>\r\n\t<li><strong>Strap-on Motors:<\/strong> In the PSLV-XL, QL, and DL variants, 6,4,2 solid rocket strap-on motors supplement the thrust delivered by the first stage.<\/li>\r\n<\/ul>\r\n<figure class=\"table\">\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td class=\"tb-color\" colspan=\"2\"><strong>Variants of PSLV<\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>PSLV-G (Standard Variant)<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- The standard PSLV configuration includes <strong>6 strap-on boosters.<\/strong><\/p>\r\n<p>- <strong>Four Stages:<\/strong> PS1, PS2, PS3, PS4.<\/p>\r\n<p>- The second PSLV flight in 1994, was successful.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>PSLV-XL (Extended Variant)<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- The XL version is launched with <strong>extra propellant<\/strong> in the strap-on <strong>solid rocket boosters<\/strong> to increase the payload capacity.<\/p>\r\n<p>- Multiple satellite launch capability and multiple orbit capability.<\/p>\r\n<p>- <strong>No. of strap-on motors:<\/strong> Six<\/p>\r\n<p>- <strong>Payload capability to SSPO (600 km):<\/strong> 1750 Kg<\/p>\r\n<p>- <strong>Launches by PSLV-XL:<\/strong> Chandrayaan-1, <strong>Aditya-L1 mission<\/strong>, and <strong>Mars Orbiter Mission<\/strong> etc.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>PSLV-CA (Core Alone Variant)<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- The Core Alone version is launched <strong>without six strap-on boosters<\/strong> and less propellant in its upper stage, a configuration specifically used in missions featuring small payloads.<\/p>\r\n<p>- This variant is the <strong>lightest version<\/strong> of the PSLV rocket.<\/p>\r\n<p><strong>- No. of strap-on:<\/strong> Nil<\/p>\r\n<p>- <strong>Payload capability to SSPO:<\/strong> 1019 Kg.<\/p>\r\n<p>- <strong>Launches:<\/strong> PSLV-C55 and<strong> PSLV-C56<\/strong>, which launched the TeLEOS-2 and DS-SAR satellites, respectively, employed the CA variant.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><strong>PSLV-QL (Quick Launch Variant)<\/strong><\/p>\r\n<p>&nbsp;<\/p>\r\n<\/td>\r\n<td>\r\n<p>- The PSLV-QL variant includes all ground-lit strap-on variants with a total propellant capacity of 48 tonnes.<\/p>\r\n<p>- <strong>No. of Strap-on:<\/strong> Four<\/p>\r\n<p>- <strong>Payload capability to SSPO:<\/strong> 1523 Kg<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>PSLV-DL (Dual Launch Variant)<\/strong><\/td>\r\n<td>\r\n<p>- The PSLV-DL variant is equipped with only two strap-on boosters with a propellant load of 12 tonnes on them.<\/p>\r\n<p>- Used for launching two satellites simultaneously.<\/p>\r\n<p>- <strong>Launches: XPoSat<\/strong><\/p>\r\n<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n<h2>Difference between PSLV and GSLV<\/h2>\r\n<p>ISRO developed two satellite launch vehicles (rockets): PSLV (Polar Satellite Launch Vehicle) and <strong>GSLV <\/strong>(Geosynchronous Satellite Launch Vehicle). <strong>The key differences between GSLV and PSLV are:\u00a0<\/strong><\/p>\r\n<figure class=\"table\">\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td class=\"tb-color\"><strong>PSLV\u00a0<\/strong><\/td>\r\n<td class=\"tb-color\"><strong>GSLV\u00a0<\/strong><\/td>\r\n<td class=\"tb-color\">&nbsp;<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Stages<\/strong><\/td>\r\n<td>4 Stage: PS1, PS2, PS3, PS4<\/td>\r\n<td>3 Stage: GS1, GS2, CUS<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Lift Off Mass<\/strong><\/td>\r\n<td>320 tonnes (XL)<\/td>\r\n<td>420 tonnes<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Fuel<\/strong><\/td>\r\n<td>Mix of solid and liquid fuels<\/td>\r\n<td>Liquified nitrogen and Oxygen<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Generation<\/strong><\/td>\r\n<td>\r\n<p>- Third Generation<\/p>\r\n<p>- First Flight: 1993<\/p>\r\n<\/td>\r\n<td>\r\n<p>- Fourth Generation<\/p>\r\n<p>- First flight: 2014<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Orbit<\/strong><\/td>\r\n<td>Capable of launching all three types of payloads: earth observation, geostationary, and navigation.<\/td>\r\n<td>GSLV is primarily used for missions to GTO.<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Used for<\/strong><\/td>\r\n<td>Designed mainly to deliver the \u201cearth-observation\u201d or \u201c<strong>remote-sensing<\/strong>\u201d satellites.<\/td>\r\n<td>The principal payloads of the GSLV are INSAT-class communication satellites that operate from geostationary orbit.<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Strap-ons<\/strong><\/td>\r\n<td>It comes with four variants: 6, 4, and 2 solid rocket strap-on motors.<\/td>\r\n<td>Four liquid strap-ons.<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Payload<\/strong><\/td>\r\n<td>1,750 kg of payload into SSPO.<\/td>\r\n<td>Payload to GTO: 2,250 kg<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Version\/Variants<\/strong><\/td>\r\n<td>PSLV-CA, PSLV-G, PSLV-XL, PSLV-DL PSLV-QL<\/td>\r\n<td>GSLV Mk 1, GSLV Mk II, <strong>GSLV Mk III.<\/strong><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n<h2>PSLV UPSC PYQs<\/h2>\r\n<p><strong>Question 1: With reference to India's satellite launch vehicles, consider the following statements: (UPSC Prelims 2018)<\/strong><\/p>\r\n<ol>\r\n\t<li>PSLVs launch satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites.<\/li>\r\n\t<li>Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.<\/li>\r\n\t<li>GSLV Mk III is a four-stage launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines.<\/li>\r\n<\/ol>\r\n<p>Which of the statements given above is\/are correct?<\/p>\r\n<p>(a) 1 only<\/p>\r\n<p>(b) 2 and 3<\/p>\r\n<p>(c) 1 and 2<\/p>\r\n<p>(d) 3 only<\/p>\r\n<p><strong>Answer: (a)\u00a0<\/strong><\/p>","protected":false},"excerpt":{"rendered":"<p>PSLV is the ISRO&#8217;s indigenously built expendable launch system. PSLV features a four-stage system that consists of solid and liquid-fuelled rocket stages.<\/p>\n","protected":false},"author":6,"featured_media":5648,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[239],"tags":[867,40],"class_list":{"0":"post-5647","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-quest-level-4","8":"tag-polar-satellite-launch-vehicle","9":"tag-quest"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/5647","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/comments?post=5647"}],"version-history":[{"count":2,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/5647\/revisions"}],"predecessor-version":[{"id":23048,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/5647\/revisions\/23048"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media\/5648"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media?parent=5647"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/categories?post=5647"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/tags?post=5647"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}